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Turner KJ, Hoyle J, Valdivia LE, Cerveny KL, Hart W, Mangoli M, Geisler R, Rees M, Houart C, Poole RJ, Wilson SW, Gestri G. Abrogation of Stem Loop Binding Protein (Slbp) function leads to a failure of cells to transition from proliferation to differentiation, retinal coloboma and midline axon guidance deficits. PLoS One 2019; 14:e0211073. [PMID: 30695021 PMCID: PMC6350959 DOI: 10.1371/journal.pone.0211073] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 01/07/2019] [Indexed: 12/26/2022] Open
Abstract
Through forward genetic screening for mutations affecting visual system development, we identified prominent coloboma and cell-autonomous retinal neuron differentiation, lamination and retinal axon projection defects in eisspalte (ele) mutant zebrafish. Additional axonal deficits were present, most notably at midline axon commissures. Genetic mapping and cloning of the ele mutation showed that the affected gene is slbp, which encodes a conserved RNA stem-loop binding protein involved in replication dependent histone mRNA metabolism. Cells throughout the central nervous system remained in the cell cycle in ele mutant embryos at stages when, and locations where, post-mitotic cells have differentiated in wild-type siblings. Indeed, RNAseq analysis showed down-regulation of many genes associated with neuronal differentiation. This was coincident with changes in the levels and spatial localisation of expression of various genes implicated, for instance, in axon guidance, that likely underlie specific ele phenotypes. These results suggest that many of the cell and tissue specific phenotypes in ele mutant embryos are secondary to altered expression of modules of developmental regulatory genes that characterise, or promote transitions in, cell state and require the correct function of Slbp-dependent histone and chromatin regulatory genes.
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Affiliation(s)
- Katherine J. Turner
- Department of Cell and Developmental Biology, Division of Biosciences, University College London, London, United Kingdom
| | - Jacqueline Hoyle
- Department of Cell and Developmental Biology, Division of Biosciences, University College London, London, United Kingdom
- Department of Paediatrics and Child Health, University College London, London, United Kingdom
| | - Leonardo E. Valdivia
- Department of Cell and Developmental Biology, Division of Biosciences, University College London, London, United Kingdom
- Center for Integrative Biology, Facultad de Ciencias, Universidad Mayor, Santiago, Chile
| | - Kara L. Cerveny
- Department of Cell and Developmental Biology, Division of Biosciences, University College London, London, United Kingdom
| | - Wendy Hart
- Department of Cell and Developmental Biology, Division of Biosciences, University College London, London, United Kingdom
| | - Maryam Mangoli
- Department of Cell and Developmental Biology, Division of Biosciences, University College London, London, United Kingdom
| | - Robert Geisler
- Karlsruhe Institute of Technology (KIT) Institute of Toxicology and Genetics, Eggenstein-Leopoldshafen, Germany
| | - Michele Rees
- Department of Paediatrics and Child Health, University College London, London, United Kingdom
| | - Corinne Houart
- Department of Developmental Neurobiology and MRC Centre for Developmental Disorders, Kings College London, London, United Kingdom
| | - Richard J. Poole
- Department of Cell and Developmental Biology, Division of Biosciences, University College London, London, United Kingdom
| | - Stephen W. Wilson
- Department of Cell and Developmental Biology, Division of Biosciences, University College London, London, United Kingdom
- * E-mail: (GG); (SWW)
| | - Gaia Gestri
- Department of Cell and Developmental Biology, Division of Biosciences, University College London, London, United Kingdom
- * E-mail: (GG); (SWW)
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Turner KJ, Hawkins TA, Yáñez J, Anadón R, Wilson SW, Folgueira M. Afferent Connectivity of the Zebrafish Habenulae. Front Neural Circuits 2016; 10:30. [PMID: 27199671 PMCID: PMC4844923 DOI: 10.3389/fncir.2016.00030] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 04/04/2016] [Indexed: 11/13/2022] Open
Abstract
The habenulae are bilateral nuclei located in the dorsal diencephalon that are conserved across vertebrates. Here we describe the main afferents to the habenulae in larval and adult zebrafish. We observe afferents from the subpallium, nucleus rostrolateralis, posterior tuberculum, posterior hypothalamic lobe, median raphe; we also see asymmetric afferents from olfactory bulb to the right habenula, and from the parapineal to the left habenula. In addition, we find afferents from a ventrolateral telencephalic nucleus that neurochemical and hodological data identify as the ventral entopeduncular nucleus (vENT), confirming and extending observations of Amo et al. (2014). Fate map and marker studies suggest that vENT originates from the diencephalic prethalamic eminence and extends into the lateral telencephalon from 48 to 120 hour post-fertilization (hpf). No afferents to the habenula were observed from the dorsal entopeduncular nucleus (dENT). Consequently, we confirm that the vENT (and not the dENT) should be considered as the entopeduncular nucleus "proper" in zebrafish. Furthermore, comparison with data in other vertebrates suggests that the vENT is a conserved basal ganglia nucleus, being homologous to the entopeduncular nucleus of mammals (internal segment of the globus pallidus of primates) by both embryonic origin and projections, as previously suggested by Amo et al. (2014).
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Affiliation(s)
- Katherine J. Turner
- Department of Cell and Developmental Biology, University College London (UCL)London, UK
| | - Thomas A. Hawkins
- Department of Cell and Developmental Biology, University College London (UCL)London, UK
| | - Julián Yáñez
- Neurover Group, Centro de Investigacións Científicas Avanzadas (CICA) and Department of Cell and Molecular Biology, University of A Coruña (UDC)A Coruña, Spain
| | - Ramón Anadón
- Department of Cell Biology and Ecology, Faculty of Biology, University of Santiago de CompostelaSantiago de Compostela, Spain
| | - Stephen W. Wilson
- Department of Cell and Developmental Biology, University College London (UCL)London, UK
| | - Mónica Folgueira
- Department of Cell and Developmental Biology, University College London (UCL)London, UK
- Neurover Group, Centro de Investigacións Científicas Avanzadas (CICA) and Department of Cell and Molecular Biology, University of A Coruña (UDC)A Coruña, Spain
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Ware M, Dupé V, Schubert FR. Evolutionary Conservation of the Early Axon Scaffold in the Vertebrate Brain. Dev Dyn 2015; 244:1202-14. [PMID: 26228689 DOI: 10.1002/dvdy.24312] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 07/20/2015] [Accepted: 07/20/2015] [Indexed: 11/11/2022] Open
Abstract
The early axon scaffold is the first axonal structure to appear in the rostral brain of vertebrates, paving the way for later, more complex connections. Several early axon scaffold components are conserved between all vertebrates; most notably two main ventral longitudinal tracts, the tract of the postoptic commissure and the medial longitudinal fascicle. While the overall structure is remarkably similar, differences both in the organization and the development of the early tracts are apparent. This review will bring together extensive data from the last 25 years in different vertebrates and for the first time, the timing and anatomy of these early tracts have been directly compared. Representatives of major vertebrate clades, including cat shark, Xenopus, chick, and mouse embryos, will be compared using immunohistochemistry staining based on previous results. There is still confusion over the nomenclature and homology of these tracts which this review will aim to address. The discussion here is relevant both for understanding the evolution of the early axon scaffold and for future studies into the molecular regulation of its formation.
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Affiliation(s)
- Michelle Ware
- Institute of Biomedical and Biomolecular Sciences, University of Portsmouth, Portsmouth, United Kingdom.,Institut de Génétique et Développement, CNRS UMR6290, Université de Rennes1, IFR140, GFAS, Faculté de Médecine, Rennes, France
| | - Valérie Dupé
- Institut de Génétique et Développement, CNRS UMR6290, Université de Rennes1, IFR140, GFAS, Faculté de Médecine, Rennes, France
| | - Frank R Schubert
- Institute of Biomedical and Biomolecular Sciences, University of Portsmouth, Portsmouth, United Kingdom
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Sun L, Chen F, Peng G. Conserved Noncoding Sequences Regulate lhx5 Expression in the Zebrafish Forebrain. PLoS One 2015; 10:e0132525. [PMID: 26147098 PMCID: PMC4492605 DOI: 10.1371/journal.pone.0132525] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2015] [Accepted: 06/15/2015] [Indexed: 01/23/2023] Open
Abstract
The LIM homeobox family protein Lhx5 plays important roles in forebrain development in the vertebrates. The lhx5 gene exhibits complex temporal and spatial expression patterns during early development but its transcriptional regulation mechanisms are not well understood. Here, we have used transgenesis in zebrafish in order to define regulatory elements that drive lhx5 expression in the forebrain. Through comparative genomic analysis we identified 10 non-coding sequences conserved in five teleost species. We next examined the enhancer activities of these conserved non-coding sequences with Tol2 transposon mediated transgenesis. We found a proximately located enhancer gave rise to robust reporter EGFP expression in the forebrain regions. In addition, we identified an enhancer located at approximately 50 kb upstream of lhx5 coding region that is responsible for reporter gene expression in the hypothalamus. We also identify an enhancer located approximately 40 kb upstream of the lhx5 coding region that is required for expression in the prethalamus (ventral thalamus). Together our results suggest discrete enhancer elements control lhx5 expression in different regions of the forebrain.
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Affiliation(s)
- Liu Sun
- Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, China
| | - Fengjiao Chen
- Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, China
| | - Gang Peng
- Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, China
- * E-mail:
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Yang B, Peng G, Gao J. Expression of unc5 family genes in zebrafish brain during embryonic development. Gene Expr Patterns 2013; 13:311-8. [PMID: 23806443 DOI: 10.1016/j.gep.2013.06.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Revised: 05/17/2013] [Accepted: 06/13/2013] [Indexed: 01/18/2023]
Abstract
UNC5 family proteins are trans-membrane receptors which mediate both repulsion and attraction signals for the axonal growth cones. The UNC5 family proteins may also play critical roles in angiogenesis and carcinogenesis. Here we have determined the temporal and spatial expression patterns of unc5 gene family members (unc5a, unc5b, unc5c, unc5da and unc5db) by RT-PCR and in situ hybridization. RT-PCR results showed that all transcripts except unc5b were expressed maternally. While unc5b and unc5c transcript was detected at all time points between shield stage and 48h post fertilization (hpf), unc5a, unc5da and unc5db showed expression at 24hpf and later time points. In situ hybridization analysis revealed that unc5a, unc5da and unc5db transcripts were expressed in the telencephalon, parts of thalamus and hindbrain between 24 and 48hpf. The expression patterns of unc5a-unc5da and unc5a-unc5db in the telencephalon showed substantial overlap by fluorescent in situ hybridization. Unc5b showed expression in the eye region, epiphysis and thalamus. Unc5c showed expression in the roof plate, the hindbrain and the mouth region. Our results provide a starting point to uncovering roles of unc5 gene family in zebrafish forebrain development and axonal outgrowth or guidance.
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Affiliation(s)
- Bin Yang
- Institutes of Brain Science and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200032, China
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Nieto-Estévez V, Pignatelli J, Araúzo-Bravo MJ, Hurtado-Chong A, Vicario-Abejón C. A global transcriptome analysis reveals molecular hallmarks of neural stem cell death, survival, and differentiation in response to partial FGF-2 and EGF deprivation. PLoS One 2013; 8:e53594. [PMID: 23308259 PMCID: PMC3538603 DOI: 10.1371/journal.pone.0053594] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Accepted: 12/03/2012] [Indexed: 11/19/2022] Open
Abstract
Neurosphere cell culture is a commonly used model to study the properties and potential applications of neural stem cells (NSCs). However, standard protocols to culture NSCs have yet to be established, and the mechanisms underlying NSC survival and maintenance of their undifferentiated state, in response to the growth factors FGF-2 and EGF are not fully understood. Using cultures of embryonic and adult olfactory bulb stem cells (eOBSCs and aOBSCs), we analyzed the consequences of FGF-2 and EGF addition at different intervals on proliferation, cell cycle progression, cell death and differentiation, as well as on global gene expression. As opposed to cultures supplemented daily, addition of FGF-2 and EGF every 4 days significantly reduced the neurosphere volume and the total number of cells in the spheres, mainly due to increased cell death. Moreover, partial FGF-2 and EGF deprivation produced an increase in OBSC differentiation during the proliferative phase. These changes were more evident in aOBSC than eOBSC cultures. Remarkably, these effects were accompanied by a significant upregulation in the expression of endogenous Fgf-2 and genes involved in cell death and survival (Cryab), lipid catabolic processes (Pla2g7), cell adhesion (Dscaml1), cell differentiation (Dscaml1, Gpr17, S100b, Ndrg2) and signal transduction (Gpr17, Ndrg2). These findings support that a daily supply of FGF-2 and EGF is critical to maintain the viability and the undifferentiated state of NSCs in culture, and they reveal novel molecular hallmarks of NSC death, survival and the initiation of differentiation.
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Affiliation(s)
- Vanesa Nieto-Estévez
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Jaime Pignatelli
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Marcos J. Araúzo-Bravo
- Laboratory of Computational Biology and Bioinformatics, Department of Cell and Developmental Biology, Max Planck Institute for Molecular Biomedicine, Muenster, Germany
| | - Anahí Hurtado-Chong
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Carlos Vicario-Abejón
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
- * E-mail:
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Robo2--slit and Dcc--netrin1 coordinate neuron axonal pathfinding within the embryonic axon tracts. J Neurosci 2012; 32:12589-602. [PMID: 22956848 DOI: 10.1523/jneurosci.6518-11.2012] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
In the embryonic vertebrate brain, early born neurons establish highly stereotyped embryonic axonal tracts along which the neuronal interconnections form. To understand the mechanism underlying neuron axonal pathfinding within the embryonic scaffold of axon tracts, we studied zebrafish anterior dorsal telencephalic (ADt) neuron development. While previous studies suggest the ADt neuronal axons extend along a commissural tract [anterior commissure (AC)] and a descending ipsilateral tract [supraoptic tract (SOT)], it is unclear whether individual ADt neuronal axons choose specific projection paths at the intersection between the AC and the SOT. We labeled individual ADt neurons using a forebrain-specific promoter to drive expression of fluorescent proteins. We found the ADt axonal projection patterns were heterogeneous and correlated with their soma positions. Our results suggest that cell intrinsic differences along the dorsal ventral axis of the telencephalon regulate the axonal projection choices. Next, we determined that the guidance receptors roundabout2 (Robo2) and deleted in colorectal cancer (Dcc) were differentially expressed in the ADt neurons. We showed that knocking down Robo2 function by injecting antisense morpholino oligonucleotides abolished the ipsilateral SOT originating from the ADt neurons. Knocking down Dcc function did not prevent formation of the AC and the SOT. In contrast, the AC was specifically reduced when Netrin1 function was knocked down. Further mechanistic studies suggested that Robo2 responded to the repellent Slit signals and suppressed the attractive Netrin signals. These findings demonstrate how Robo2-Slit and Dcc-Netrin coordinate the axonal projection choices of the developing neurons in the vertebrate forebrain.
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